Treatment of wool with isocyanateepichlorohydrin mixtures



United States Patent F 3,156,522 TREATMENT OF WOOL WITH ISOCYANATE- EPICHLOROHYDRIN MIXTURES Nathan H. Koenig, Berkeley, Calif., assignor to the United tates of America as represented by the Secretary of Agriculture No Drawing. Filed Nov. 29, 1962, Ser. No. 241,078 8 Claims. (Cl. 8--127.6) (Granted under Title 35, US. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates broadly to the chemical modification of wool. In particular, the invention concerns and has as its prime object the provision of novel processes wherein wool is chemically modified by reacting it with a mixture of an organic isocyanate and epichlorohydrin. Further objects of the invention will be apparent from the following description wherein parts and percentages are by weight unless otherwise specified.

Although wool is a very useful fiber it is often desirable to improve its properties for particular applications by chemically modifying it. Various compounds have been proposed for reaction with wool to produce modified fibers. It is known, for example, that wool can be chemically modified by reacting it with an isocyanate. It is also known that wool can be chemically modified by reacting it with epichlorohydrin.

It has now been found that when wool is reacted with a mixture containing both an isocyanate and epichlorohydrin, superior results are attained as compared with the reaction of wool with the individual compounds. A primary advantage of the process of the invention is that it yields an unexpectedly high degree of modification of the Wool. This unusual result of the invention is demonstrated by the following comparative experiments:

Example I (a) Reaction of wool with a mixture of isocyanate and epichlorohydrin: Dry wool cloth (1.2 g.), p-chlorophenyl isocyanate (2 ml.), and epichlorohydrin (5 ml.) were heated at 105 C. for 90 minutes. The treated wool was successively extracted with warm acetone and hot ethanol to remove unreacted reagents, then dried. It was found that the increase in the weight of the wool, due to its combination with the isocyanate and epichlorohydrin, was 60%.

(b) Reaction of wool with isocyanate: Dry wool cloth (1.2 g.) and p-chlorophenyl isocyanate (7 ml.) were heated at 105 C. for 90 minutes. The wool was extracted as described in Part (a) and dried. It was found that the increase in weight of the wool was 5% (0) Reaction of wool with epichlorohydrin: Dry wool cloth (1.2 g.) and epichlorohydrin (7 ml.) were heated at 105 C. for 90 minutes. The wool was extracted as described in Part (a) and dried. The increase in the weight of the wool was 20% I The above results are summarized below:

It is evident fromthe above data that the process of the invention achieves a degree of modification which is 3,156,522 Patented Nov. 10, 1964 far greater than the expected additive effect. In other words, by employing a mixture containing both the isocyanate and epichlorohydrin, I obtain a synergistic effect. Since the process of the invention yields wools of an enhanced degree of modification as compared with those prepared under comparable conditions with an isocyanate or epichlorohydrin alone, it has the practical advantage of yielding products which exhibit greater resistance to deleterious agents or influences, such as bleaching agents, acidic conditions, laundering media, etc. Another advantage of the process is that the improvement is essen tially permanent; the treated materials do not lose their new properties after long use or cleaning but retain these properties for the life of the material.

Carrying out the process of the invention essentially involves contacting wool with a mixture of the isocyanate and epichlorohydrin. The reaction conditions such as proportion of reagents, specific isocyanate used, time, temperature, etc. are not critical and may be varied to suit individual circumstances without changing the basic nature of the invention. The mixture of isocyanate and epichlorohydrin is generally selected to contain from 5 to 95% of isocyanate and the remainder (95 to 5%) of epichlorohydrin. The temperature of reaction may be from 50 to 125 C. The reaction rate is increased with increasing temperature and a preferred range to expedite the reaction, yet without damaging the'wool, is 100-115 .C. It is preferred to carry out the reaction under anhydrous conditions, thereby to ensure reaction of the wool .used.

with the modifying agents (isocyanate and epichlorohydrin) and to suppress the formation of insoluble byproducts as mere coatings on the wool. The reaction can be applied to wool in its normal undried condition (containing about 12 to 14% water) but in such case, the

reaction between the wool and the modifying agents will be accompanied by formation of insoluble by-products which deposit on the wool fibers. The degree of modification of the wool is influenced by the proportion of modifying agents taken up by the fiber; that is, the higher the uptake of isocyanate and epichlorohydrin the greater will be the degree of modification of the wool. In general, the uptake of isocyanate and epichlorohydrin may be varied from 1 to In conducting the reaction the mixture of isocyanate and epichlorohydrin is generally employed in excess over the amount desired to be taken up by the fibers. The time of reaction will vary depending on such factors as the proportion of modifying agents, temperature of reaction, reactivity of the isocyanate selected, and the degree of modification desired. In general, the reaction may take anywhere from a few minutes to several hours. The reaction may be conducted in the presence of conventional inert solvents such as toluene, xylene, benzene, chlorobenzene, or the like.

After reaction of the wool with the mixture of isocyanate and epichlorohydrin, the chemically modified wool is treated to remove excess reagents andsolvent, if such is Thus the wool may be treated as by wringing, passage through squeeze rolls, centrifugation, or the like. In place of such mechanical action, or in addition thereto, the modified wool product may be extracted with a solvent such as trichloroethylene, benzene, acetone, ethanol, carbon tetrachloride, etc. Successive extractions with different solvent may be applied to ensure complete removal of all unreacted materials. The treated wool is then dried in the usual way. a

Wool modified in accordance with the invention exhibits advantageous properties over normal wool. For example, the modified wool is more resistant to oxidizing conditions. Such conditions may be encountered in textile millsduring bleaching, shrinkproofing, or other finishing processes. Oxidizing environments also occur in use by the action of light and air, and in laundering by bleaching chemicals. The increased resistance to oxidizing conditions has been shown by exposing normal and modified wool samples to solutions of sodium hypochlorite, which is used in commercial bleaches.

The tendency of wool to shrink when subjected to washing in aqueous media has long been a deterrent to the more widespread use of wool. An advantage of the invention is that it yields modified wools which have a decreased tendency to shrink when subjected to Washing with conventional soap and water or detergent and water formulations.

Although the properties of the modified wool indicate beyond question that actual chemical combination between the isocyanate and epichlorohydrin has taken lace, it is not known for certain how these chemicals are united with wool. It is believed, however, that the isocyanate and epichlorohydrin react with the sites in the Wool molecule where there are reactive hydrogen atomsthese include such groups as amino, hydroxyl, thiol, phenolic, amide, guanidino, imidazoyl, and carboxyl. it may be, however, that other reactions occur and I do not intend to limit the invention to any theoretical basis. It is to be noted that the reaction in accordance with the invention does not impair the wool fiber for its intended purpose, that is, for producing woven or knitted textiles, garments, etc.

The process of the invention may be applied to wool in the form of fibers, as such, or in the form of threads, yarns, slivers, knitted or woven goods, felts, etc. The Wool textiles may be White or dyed goods and may be of all-wool composition or blends of W001 with other textile fibers such as cotton, regenerated cellulose, viscose, animal hair, etc.

The process of the invention is not restricted to any particular isocyanate or class of isocyanates. Consequently, the invention may be applied in the reaction of wool with a mixture of epichlorohydrin and any type of organic isocyanate. Particularly preferred are the aliphatic, aromatic, or aromatic-aliphatic compounds containing one or more isocyanate groups. These compounds may be hydrocarbon isocyanates or may contain substituents on the hydrocarbon residue, such as halogen (chlorine, bromine, iodine, and fluorine), ether groups, ester groups, nitro groups, etc. Examples of compounds coming into the purview of the invention are listed below by way of illustration and not limitation:

Typical examples of compounds in the category of aliphatic isocyanates are methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl (normal, iso, secondary, or tertiary) isocyanate, amyl isocyanate, isoamyl isocyanate, hexyl isocyanate, octyl isocyanate, Z-ethylhexyl isocyanate, decyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate, octadecyl isocyanate, oleyl isocyanate, allyl isocyanate, crotyl isocyanate, cyclohexyl isocyanate, methylcyclohexyl isocyanate, Z-chloroethyl isocyanate, Z-bromoethyl isocyanate, 2-iodoethyl isocyanate, Z-fiuoroethyl isocyanate, ll-chlorodoclecyl isoeyanate, 4-chlorocyclohexyl isocyanate, Z-methoxyethyl isocyanate, Z-ethoxyethyl isocyanate, Z-butoxyethyl isocyanate, carbethoxymethyl isocyanate, ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octarncthylene diisocyanate, decamethylene diisocyanate, cyclohexylene diisocyanate, bis (2-isocyanatoethyl) ether, bis (Z-isocyanatoethyl) ether of ethylene glycol, l-chloropropane-2,3-diisocyanate, etc.

Typical examples of compounds in the category of aromatic isocyanates are phenyl isocyanate, o-tolyl isocyanate, m-tolyl isocyanate, p-tolyl isocyanate, xylyl isocyanate, alpha-naphthyl isocyanate, dodecylphenyl isocyanate, cyclohexylphenyl isocyanate, biphenylyl isocyanate, benzylphenyl isocyanate, o-chlorophcnyl isocyanate, m-chlorophenyl isocyanate, p-chlorophenyl isocyanate, 2,5-dichlorophenyl isoeyanate, p-bromophenyl isocyanate,

o-methoxyphenyl isocyanate, p-methoxyphenyl isocyanate, o-ethoxyphenyl isocyanate, p-ethoxyphenyl isocyanate, m-nitrophenyl isoeyanate, p-nitrophenyl isocyanate, o-phenylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, to1ylene-2,4-diisoeyanate, tolylene-2,6-diisocyanate, 3,3'-bitolylene-4,4'-diisocyanate, 3,5, 3',5'-bixylylene-4,4-diisocyanatc, i.e.-

(wherein R is CH diphenylrnethane-4,4'-diisocyanate, biphenylene-4,4'-diisocyanate, 3,3-dimethoxybiphenylene-4,4'-diisocyanate, naphthalene diisocyanates, polymethylene polyphenyl isocyanates, etc.

Typical examples of aromatic-aliphatic isocyanates are benzyl isocyanate, chlorobenzyl isocyanates, methylbenzyl isocyanates, methoxybenzyl isocyanates, nitrobenzyl isocyanates, 2-phenoxyethyl isocyanate, 2benzoxyethyl isocyanate, etc.

The invention is further demonstrated by the following illustrative examples:

Example II (a) A 1.8-gram sample of dry wool cloth was heated with 2 ml. of phenyl isocyanate and 5 ml. of epichlorohydrin for minutes at C. The treated wool was extracted as in Example I, Part (a), and dried. The increase in the weight of the wool was 43%.

For comparative purposes the following experiments were carried out:

(b) Dry wool cloth (1.8 g.) and phenyl isocyanate (7 ml.) were heated for 90 minutes at 105 C. The treated wool was extracted as described in Part (a) and dried. The increase in weight of the wool was 8%.

(0) Dry wool cloth (1.8 g.) and cpichlorohydrin (7 ml.) were heated for 90 minutes at 105 C. The treated Wool was extracted as described in Part (a), and dried. The increase in weight of the wool was 16%.

Example 111 A sample of the product of Example I, Part (a)-made by reacting wool with p-chlorophenyl isocyanate and epichlorohydrinwas tested to determine its resistance to hypochlorite. For comparison purposes, the same test was applied to the untreated wool and to the wools modified as disclosed in Example I, Parts (b) and (c), these latter representing wool treated solely with p-chlorophenyl isocyanate or solely with epichlorohydrin.

The hypochlorite resistance test was performed as follows:

A 2-cm. length of yarn was removed from the fabric and placed in a 50-ml. beaker containing 20 m1. of 3% aqueous sodium hypochlorite. The liquid was stirred magnetically until the yarn had dissolved and the elapsed time was noted.

The results tabulated below show the increased resistance to sodium hypochlorite of Wool modified in accordance with the invention.

Example IV A sample of the product of Example I, Part (a)madc by reacting wool with p-chlorophenyl isocyanate and epichlorohydrin-was tested to determine its shrinkage characteristics. For purposes of comparison, the same test was applied to a sample of the untreated wool and 5 t the wools modified as disclosed in Example I, Parts (11) and (c), these latter representing wool treated solely with p-chlorophenyl isocyanate or solely with epichlorohydrin.

The shrinkage tests were carried out as follows:

The wool samples were violently agitated in an Accelerotor at 1700 r.p.m. for 6 minutes at 40-42 C. with 0.9% sodium oleate solution, using a liquor-to-wool ratio of 50 to 1. The area of the samples was measured before and after this laundering process. The improvement in shrinkage properties of wool modified in accordance with the invention is demonstrated by the following data:

Area Reagents used in modifying wool shrinkage,

percent p-Ohlorophenyl isocyanate and epichlorohydrin, Ex. I, (a). 0 p-Chlorophenyl isocyanate, Ex. I, (b) 42 Epichlorohydrin, Ex. I, (c) 49 None (untreated Wool) 51 Example V A 1.2-gram sample of dry wool cloth was heated with 2 ml. of p-bromophenyl isocyanate and 5 ml. of epichlorohydrin for 90 minutes at 105 C. The treated wool was extracted as in Example I, Part (a), and dried. The increase in the weight of the wool was 80%.

6 Example VII A 1.2-gram sample of dry wool cloth was heated with 1 ml. of 3,5,3',5'-bixylylene-4,4-diisocyanate and 4 ml. of epichlorohydrin for minutes at 105 C. The treated wool Was extracted as in Example I, Part (a), and dried. The increase in the weight of the Wool was 19%. A sample of the product was then tested for shrinkage according to the procedure of Example IV. The area shrinkage in this test was 10%.

Having thus described the invention, what is claimed is:

1. A process for chemically modifying wool which comprises reacting wool under anhydrous conditions with a mixture containing 5 to by weight of epichlorohydrin and 95 to 5% by weight of an organic isocyanate selected from the group consisting of aliphatic, aromatic, and aromatic-aliphatic isocyanates.

2. The process of claim 1 wherein the cyanate is an aliphatic isocyanate.

3. The process of claim 1 wherein the cyanate is phenyl isocyanate.

4. The process of claim 1 wherein the cyanate is chlorophenyl isocyanate.

5. The process of claim 1 wherein the cyanate is bromophenyl isocyanate.

6. The process of claim 1 wherein the cyanate is bixylylene diisocyanate.

7. The process of claim 1 wherein the cyanate is aliphatic isocyanate.

8. The process of claim 1 wherein the cyanate is an aromatic-aliphatic isocyanate.

organic isoorganic isoorganic isoorganic isoorganic isoorganic isoorganic iso- References Cited in the file of this patent UNITED STATES PATENTS 2,594,979 Nelson Apr. 29, 1952 2,602,075 Stanley July 1, 1952 2,799,663 Hampton July 16, 1957 2,850,408 Zurawic Sept. 2, 1958 2,933,409 Binkley Apr. 19, 1960 FOREIGN PATENTS 540,613 Great Britain Oct. 23, 1941 

1. A PROCESS FOR CHEMICALLY MODIFYING WOOL WHICH COMPRISES REACTING WOOL UNDER ANHYDROUS CONDITIONS WITH A MIXTURE CONTAINING 5 TO 95% BY WEIGHT OF EPICHLOROHYDRIN AND 95 TO 5% BY WEIGHT OF AN ORGANIC ISOCYANATE SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC, AROMATIC, AND AROMATIC-ALIPHATIC ISOCYANATES. 